In recent years, the Web Service Definition Language (WSDL) and Universal Description Discovery Integration (UDDI) standards arose as ad hoc standards for the definition of service interfaces and service registries. However, even together these standards do not provide enough basis for a service consumer to get a full understanding of the behavior of a service. In practice, this often leads to a serious mismatch between the provider's intent and the consumer's expectations concerning the functionality of the corresponding service. Though additional standards have been proposed, a holistic view of what aspects of a service need to be specified is still lacking. This paper proposes a service definition, a service classification, and service specification framework, all based on a founded theory, the $(\Psi)$-theory. The $(\Psi)$-theory originates from the scientific fields of Language Philosophy and Systemic Ontology. According to this theory, the operation of organizations is all about communication between and production by social actors. The service specification framework can be applied both for specifying human services, i.e., services executed by human beings, and IT services (i.e., services executed by IT systems).